[Authlib] Add requests as an optional dependency (#16015)

Author: srittau

stubs/Authlib/@tests/stubtest_allowlist.txt

@@ -49,6 +49,5 @@ authlib.integrations.flask_client.*
 authlib.integrations.flask_oauth1.*
 authlib.integrations.flask_oauth2.*
 authlib.integrations.httpx_client.*
-authlib.integrations.requests_client.*
 authlib.integrations.sqla_oauth2.*
 authlib.integrations.starlette_client.*

stubs/Authlib/METADATA.toml

@@ -1,3 +1,4 @@
 version = "1.7.2"
 upstream-repository = "https://github.com/authlib/authlib"
 dependencies = ["cryptography"]
+optional-dependencies = ["requests"]